Wait until February 1st, when TMDSAS tells you that you didn't match anywhere. Then you check an hour later, just as you've accepted that you weren't admitted anywhere, and you discover you actually matched to your first choice school! OR, you enter all your grades and expect TMDSAS to show your 3.8 GPA but the app messes up and shows you have a 3.2.
This stuff didn't actually happen to me (THANK GOODNESS), but it has been happening to many people. TMDSAS's new layout (its only the second year of it I think?) is very nice, but also very glitchy. Good thing they are helpful and quick to respond!!!